The skin care industry thrives on buzzy terms. “Barrier protection” and “collagen stimulating” are just a few examples of how shopping for new products can feel like a college biology course. But at its core, skin care is science, and even the most basic phrases have deeper meanings. Take water retention, for example. As one of the key principals of any good routine, there are a number of creams and serums aimed to get rid of dryness. However, there is a big difference between moisturizing and hydrating your skin.
Though often used interchangeably, these two words are quite different. “They sound similar in concept, and you absolutely need both to achieve healthy skin,” says Dr. Ryan Turner, M.D., New York City-based board-certified dermatologist and co-founder of TRNR Skin. As he explains, water is the underlying connection, but their functions are different. “Hydration is all about pulling water into the surface layers of the skin while moisturizing is about trapping it within to support and strengthen its barrier,” he says.
Doing one without the other isn’t very beneficial. So, when it comes to building a routine, what should you really be looking for? Ceramides, humectants, and hyaluronic acid are all popular ingredients aimed to help you quench and replenish your skin. But shopping can be overwhelming, so understanding the fundamentals will ensure that you’re using the right products.
Below, TZR spoke with dermatologists to learn how moisturizing ingredients differ from hydrating ones and how to tell when your skin needs one over the other.
The Difference Between Moisturizing & Hydrating
The dictionary defines hydrating as the process of water absorption and moisturizing as the act of adding moisture. For skin care, this means hydrating products should sink into your skin below the surface, while moisturizers should act more like a sealant.
Water is an important factor in keeping the cells plump and maintaining elasticity. But it can easily evaporate, leaving your skin dehydrated and dull. By adding a layer to the outside, you can lock the molecules inside so they stay put longer. “If you think of your skin barrier as a wall, the cells are like the bricks that build the structure while the lipids and ceramides work like grout holding them together to keep water from escaping,” says Dr. Turner. He continues noting that this is why barrier protection is crucial. “Transepidermal water loss (TEWL) is exacerbated by a weak skin barrier. If you’re just applying hydrating products to your skin without fortification from moisturizers, the hydrators cannot work effectively,” he says.
How Can You Tell If Your Skin Is Lacking Moisture Or Hydration?
“Dry skin is a skin type characterized by minimal sebum output due to varying reasons such as exposure to extreme temperatures or decreased oil production which can change with age,” says Dr. Turner. On the other hand, dehydration can occur in any skin type, including oily and combination, and is usually caused by a lack of water intake, sleep, or environmental stressors. If the skin barrier is compromised, the microbiome may not be able to defend itself as well, leaving the skin more susceptible to irritation and sensitivity. According to Dr. Sheila Farhang, M.D, a board-certified dermatologist in Tucson, Ariz., to effectively restore the barrier you need to use a moisturizer and not a hydrator. She tells TZR that emollient-rich products will provide support and help restrengthen it.
The telltale signs of dehydrated skin are typically dullness and a lackluster appearance that makes fine lines more visible. If your skin is in need of hydration, both experts note that a combination of humectant ingredients is the key to drawing in water and rehydrating cells. However, Dr. Farhang advises assessing your skin’s needs and the environment around you first. “If you’re in a dryer climate, the air can pull water out of your skin. And if you’re using too many hydrating ingredients when your skin is not properly moisturized, the symptoms of dryness, like flaking, are likely to increase,” she says.
Moisturizing Vs. Hydrating Ingredients
In the world of skin care, face creams are often referred to as moisturizers, but a quick scan of the INCI list will tell you whether the product is moisturizing or hydrating. “Oils, ceramides, lipids, and petroleum are all examples of moisturizing ingredients that will help support the skin barrier,” says Dr. Farhang. In that vein, Dr. Turner adds that while some are naturally found within the skin, others, such as jojoba oil, squalane, and shea butter, can be extracted from plants and added to a product. Since these ingredients are meant to seal in water, they’re usually the last step of a routine and are found in creams or face oils.
As for hydrating ingredients, the experts note that they are most often humectants that work by attracting water to the skin. “The most well-known humectant is hyaluronic acid, a sugar molecule naturally found in the human body, and plant-derived glycerin and aloe,” says Dr. Turner. These can be found in a variety of products, including cleansers, serums, and creams, injecting water into the cells with use.
How To Effectively Moisturize & Hydrate Your Skin
While your skin needs both steps, the ingredients need to be applied in the correct order to reap the benefits. Hydrators are lighter than moisturizers, therefore they need to be used first to be absorbed beyond the barrier. Though most products make building a routine easy, Dr. Turner notes that using a multi-tasking formula that addresses both hydration and moisture can help streamline your steps. “Ideally you want to promote balance. Prioritizing both moisturizing and hydrating will be the difference between healthy, glowing skin, and a dry, lackluster appearance.”